The present invention relates to novel iridium-based Ir(III) luminescent complexes, conjugates comprising these complexes as a label and their application, e.g. in the electrochemiluminescence based detection of an analyte.
Electrogenerated chemiluminescence (also called electrochemiluminescence and abbreviated ECL) is the process whereby species generated at electrodes undergo high-energy electron-transfer reactions to form excited states that emit light. The first detailed ECL studies were described by Hercules and Bard et al. in the mid-1960s. After about 50 years of study, ECL has now become a very powerful analytical technique and is widely used in the areas of, for example, immunoassay, food and water testing, and biowarfare agent detection.
There is a tremendeous number of compounds that appears to be of interest for use in organic light emitting devices (OLEDs). These compounds are appropriate for use in solid materials or may be dissolved in organic fluids. However, no conclusion can be drawn regarding their utility in an aqueous medium as e.g., required for detection of an analyte from a biological sample.
In general ECL-based detection methods are based on the use of water-soluble ruthenium complexes, comprising Ru(II+) as metal ion.
Despite significant improvements made over the past decades, still a tremendous need exists for more sensitive electrochemiluminescence-based in vitro diagnostic assays.
It has now been surprisingly found that certain iridium-based Ir(III+) luminescent complexes, represent very promising labels for future high sensitive ECL-based detection methods.